It should not be possible to withdraw the strap from the body by moving the ratchet teeth in the reverse direction past the resiliently deformable catch.
As a result, when the tamper resistant seal is used in conjunction with a cash box, for example, it should not be possible to open the cash box without necessarily breaking or at least damaging the tamper resistant seal.
Typically, the ratchet teeth are of frusto-conical form and the resiliently deformable catch is formed from three fingers which extend longitudinally from a common circumferentially continuous base.
The fingers are flexed outwardly as a leading conical part of each ratchet tooth is moved therepast, and simultaneously snap inwardly as a trailing flat part of each ratchet tooth is moved therepast.